Harness for supporting high pressure electric discharge tube within outer envelope and lamp formed thereby

ABSTRACT

A support harness for an arc tube of high-pressure electric discharge lamp is described herein. The arc tube of the lamp is provided with preformed notches in its press seal portion. A pair of formed support straps coincidental in shape to the preformed notches are placed over the notches and are welded at their outer ends to securely hold the arc tube in axial alignment within the envelope of the lamp.

United States Patent 1191 Peterson et a1.

HARNESS FOR SUPPORTING HIGH 1 Jan. 30, 1973 3.424.935 1/1969 Gungle et a]. 313/184 X 2,918,592 12/1959 Pomfrett et a] A ..3l3/25 2,901,648 8/1959 Linsday et a1. ....313/25 3,094,640 6/1963 Gustin ..313/25' Primary ExaminerPalmer C. Demeo AltorneyNorman J. OMalley and Joseph C Ryan [57] ABSTRACT A support harness for an arc tube of high-pressure electric discharge lamp is described herein. The are tube of the lamp is provided with preformed notches in its press seal portion. A pair of formed support straps coincidental in shape to the preformed notches are placed over the notches and are welded at their outer ends to securely hold the arc tube in axial alignment within the envelope of the lamp.

3 Claims, 3 Drawing Figures PATENTEUJAHBO ms 3.714.485

CA'RL PETERSON EDWARD A. WEBB INVENTORS BY 0 ATTORNEY HARNESS FOR SUPPORTING HIGH PRESSURE ELECTRIC DISCHARGE TUBE WITHIN OUTER ENVELOPE AND LAMP FORMED THEREBY BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to high-pressure, electric discharge lamps and more particularly to an improved arc tube and its support, generally called a harness.

High pressure electric discharge lamps are well known in the art and comprise an outer light-transmitting envelope and an inner arc tube with electron emitting electrodes between which an arc discharge is established through vaporized, ionized mercury fill in the lamp. The inner arc tube is supported within the outer envelope by a tube support generally called a harness.

The fabrication of the harness is very important to the final lamp operation. Basically, the arc tube must be held stable and axially aligned within the envelope of the lamp during the life of the lamp. The harness generally comprises a large number of structurally stable bent wires, stable bent wires, straps and metal supporting brackets which are spot welded together in separate fabrication steps.

Usually in this construction, the arc tube is held in axial alignment within the lamp envelope by cross arms projecting from a main harness support. These arms are formed around the flat press seal of the arc lamp, the ends are bent toward each other and the support frame wires are spot welded between the ends of the straps.

This method of supporting the arc tube is widely used in the art and has proved satisfactory in many applica tions, with the exception however of the lamps that are used in areas of excessive vibrations such as bridges etc.

2. Prior Art Over the years, harness structures have changed from bulky and expensive construction to a simpler harness. This change was due to the change in the arc tube from a round seal to a flat press seal. In supporting the flat press seal arc tubes, either a harness stamped from one piece of metal was used or individual loops at each end of the arc tube. In each case, the arc tube was supported by cross support members extending from the main harness frame. These cross support members were formed to conform to the shape of the seal and their ends were welded together as well as to the main harness frame. This arrangement held the arc tube in a relatively rigid position. But the main disadvantage of this type of support was that vibration of the lamp during its operation tended to loosen the arc tube from the cross support members. In recent years the high pressure arc lamp application has expanded to areas where vibration is common, such as bridge and outdoor stadium lighting. With these applications, it is very important to provide a harness support with positive arc tube holding qualities. 7

SUMMARY OF THE INVENTION In our invention we have designed a lamp harness that provides an inexpensive means for securing an arc tube within a glass envelope ofa lamp, and holding it in axial alignment throughout its life even during applications where vibrations are continuous. Briefly, we have found by using inexpensively formed cross support members and designing them to fit to mating formed notches in the press seal of the arc tube, the tube will be securely held without working loose during the life of the lamp. 2

DESCRIPTION OF THE FIGURES SPECIFIC EMBODIMENT OF THE INVENTION In one embodiment we have designed a unique harness arrangement in which the arc tube is securely locked to the harness throughout the life of the lamp.

We provide the flat press seal portion of the arc tube with formed notches oppositely disposed from one another at each side of the press seal. A pair of mating preformed metal cross support members are provided for each end of the seal. Each of the metal cross supports is formed with an offset portion, the offset being equal to the thickness of the press seal, and each offset lying out of register with the offset of the other support. With this arrangement the cross supports fit over the press seal area with one offset of the supports fitting into each notch formed in the press seal. The ends of the metal cross supports and the main legs of the harness are welded together. In this way, the offset portions of the cross supports are located within the confines of the notches and provide a reliable locking arrangement for the arc tube.

In FIG. 1 an elevational view of a high-pressure electric discharge lamp is shown. The harness 10 for supporting the arc tube 12 is positioned in the central portion of the bulbous envelope 14. In order to obtain the maximum efficiency for the lamp, it is conventional practice to axially align the arc tube 12 in the bulbous envelope. This is accomplished by the harness 10 which comprises an upper support loop 16 and a lower support loop 18. The support loops l6 and 18 are provided with resilient bumpers or spacers 22 and 24 respectively, located at the top closed ends of the loops l6 and 18 and in register with a circular protuberance of the lamp envelope. These bumpers maintain co-axial positioning of the harness and the arc tube when the lamp is subjected to shocks such as shaking and jarring.

Sealing of the glass envelope I4 and making of the electrical connections are effected in the conventional way such that a threaded base 26 is applied to the sealed off restriced end of the lamp envelope 14. A stem 30 at the sealed end of the envelope 14 extends within the envelope 14 and supports lead-in wires 32 and 33, one end of one of these lead-in wires being directed to contact button 34 that is spaced and insulated from the threaded base 26 by a glass insulator ring 36. The other lead-in wire is welded to the inside of the threaded base 26. The internal ends of lead-in wires 32 and 33 extend from the stem press 30 and are connected to electrodes 42 and 43 sealed at each end of the arc tube 12. The top electrode 42 is connected to lead-in wire 33 of metal ribbon 40 and rod 41, the lower electrode 43 is electrically connected by way of rod .45 and a short metal ribbon 44 of frame 18 and thence to lead-in wire 32. A starting probe 44 located adjacent to the lower electrode 43 is connected to leadin wire 33 by way of rod 47 and resistor 46.

The ends of the arc tube 12 are flattened or pinched to insure proper sealing therein of the electrical rods.

In our design the arc tube flat press seals are formed specifically to have oppositely disposed notches 50, one end of which is in detail in Fig. 2. A pair of cross support members 52 each have offsets 54 at each end thereof. The offsets 54 are equal in size to the notches 50 formed in the press seals of the arc tube. As noted in comparison of FIGS. 2 and 3, the support members are shown prior to assembly in FIG. 2 and when they are welded together as shown in FIG. 3. In FIG. 3 it can be seen that only small portions of the upper support loop 16 are shown. This same welding arrangement is made at the other end of the arc tube with the cross members 52 joined in the loop 18. In FIG. 3, the cross support members 52 and the loop 16 are welded together and the fitting of the notches 50 and the offsets 54 insure a positive locking arrangement for the arc tube.

It is apparent that changes and modifications may be made within the scope of the instant invention. It is our intention, however, to be limited only by the scope of the appended claims.

As our invention, we claim:

1. A high pressure discharge lamp comprising:

an arc tube having flattened end portions, said end portions being provided with retaining-means;

a transparent outer bulbous envelope around said are tube but spaced therefrom;-

a harness for supporting said are tube within said envelope, said harness having an upper wire loop and a lower wire loop, each of the open ends of said wire loops stradling said flattened end portions of said are tube, and mating cross support members having locking means, the ends of each support members being fixedly attached to the ends of the said loops, and said locking means cooperating with said retaining means of said flattened end portions of said are tube thereby securely holding said are tube in axially alignment within the transparent outer envelope.

2. The lamp according to claim 1 wherein said retaining means comprises a pair of notches at each side of said flattened end portion of said are tube. V

3. The lamp according to claim 1 wherein said locking means of said support members comprise offset portions equal in size to the retaining means of said are tube. 

1. A high pressure discharge lamp comprising: an arc tube having flattened end portions, said end portions being provided with retaining means; a transparent outer bulbous envelope around said arc tube but spaced therefrom; a harness for supporting said arc tube within said envelope, said harness having an upper wire loop and a lower wire loop, each of the open ends of said wire loops stradling said flattened end portions of said arc tube, and mating cross support members having locking means, the ends of each support members being fixedly attached to the ends of the said loops, and said locking means cooperating with said retaining means of said flattened end portions of said arc tube thereby securely holding said arc tube in axially alignment within the transparent outer envelope.
 1. A high pressure discharge lamp comprising: an arc tube having flattened end portions, said end portions being provided with retaining means; a transparent outer bulbous envelope around said arc tube but spaced therefrom; a harness for supporting said arc tube within said envelope, said harness having an upper wire loop and a lower wire loop, each of the open ends of said wire loops stradling said flattened end portions of said arc tube, and mating cross support members having locking means, the ends of each support members being fixedly attached to the ends of the said loops, and said locking means cooperating with said retaining means of said flattened end portions of said arc tube thereby securely holding said arc tube in axially alignment within the transparent outer envelope.
 2. The lamp according to claim 1 wherein said retaining means comprises a pair of notches at each side of said flattened end portion of said arc tube. 